Case

A 43yo is involved in a motor vehicle accident. The driver used a standard three point restraint in a sedan vehicle and was impacted in the side by a pickup truck. The patient has multiple injuries including a displaced left arm mid-humeral fracture causing considerable mid-arm pain. The patient indicates an inability to open their left hand and loss of sensation to a portion of their left hand. Their hand is warm and the patient is able to grasp your hand with theirs

Question 1/3 - Injury to which structure(s) most concern you in this patient?

Click on your selected option(s) below  (correct = 1, over-thinking = 2+)

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Incorrect. This injury is Klumpe's palsy, the classic mechanism of injury is usually a raise arm stretch and is a more proximal injury (roots), not a mid-humeral fracture.

Incorrect. This is an Erb's palsy characterized by an arm in the 'waiters tip' posture. While the wrist is in a flexion posture, the fingers are able to extend. Additionally the classic mechanism of injury is a stuck shoulder pediatric injury and is a more proximal injury (roots), not a mid-humeral fracture.

Incorrect. Pectoral nerves emerge from the lateral and medial cords of the brachial plexus and are then more proximal to the injury point mid-humeral. Thus, these are unlikely to be involved in the humeral injury.

Incorrect. The axillary nerve can be at risk with humeral fractures, this is typically from more proximal fractures (anatomic/surgical neck fractures). This is the A in the ARM mnemonic. 

Incorrect. The ulnar nerve courses in the soft tissue of the arm distant from the bone, it is rarely involved with mid-humeral fracture.

Incorrect. While the median nerve can be at risk with humeral fractures, it is typically as a consequence of distal fracture (e.g. supracondylar fracture). Injury would affect finger flexion, not extension.

Correct! The radial nerve is vulnerable to injury as it spirals around the humerus mid-shaft. This is the R in the mnemonic ARM in humeral fractures, which stands for Axillary (proximal fractures), Radial (mid-shaft fractures), and Median (distal fractures).